Intelligent network telephone call processing is now quite common. For example, when an "800" number or "toll-free" number is dialed, the call can be routed to a regular telephone number, and the charge for that call may be billed to the called number. In order to process the call, a database is queried to determine or define the actual destination for the call. Characteristics concerning the handling of the call, such as routing, can thus involve not only the dialed number, but also various other factors, such as the location where the call originated, information indicating the history of the caller, and the day of the week or the time of day that the call is being made.
FIG. 1 shows in simplified form an intelligent telephone network 100. Telephone network 100 comprises originating stations 102 and 104, destination stations 114 and 116, and long-distance network 118, illustratively the AT&T network. Originating stations 102 and 104 are representative of a plurality of network endpoints, the remainder of which are not shown for clarify of exposition. Only those portions of the telephone network necessary for completing calls from an originating station to a destination station are shown.
LEC networks 106, 108, 110, and 112 contain switching machines 120, 122, 124, and 126, respectively. Switching machines 120, 122, 124, and 126 are capable of connecting to the long distance network 118. Such switching machines are well known and may be, for example, AT&T 5ESS.RTM. switch. Long distance network 118 comprises switching machines 128 and 130, network control point (NCP) 132 and optional adjunct processor 136. NCP 132 is of a type well known in the art, an example of which is disclosed in U.S. Pat. No. 4,191,860. Switching machines 128 and 130, NCP 132, and AP 136 are interconnected in the manner shown by signaling network 138, represented by dashed lines. Signaling network 138, which may be an SS7 system, for example, allows switching machines 128 and 130 to query NCP 132. Information received in response to such queries may be returned to the switch in the form of data messages. Originating stations 102 and 104, destination stations 114 and 116, switching machines 120, 122, 124, and 126, and switching machines 128 and 130 are interconnected by information links 140 in the manner shown. Information links 140 are of well known types for interconnecting communicating apparatus and can carry at least voice, data and video.
Depending upon the particular arrangement of the elements in network 100, switch 128 may, responsive to receipt of a dialed number recognized as a number requiring "intelligent call processing," launch a query, via the signaling network 138, to the NCP 132, in order to retrieve a destination number that is associated with the dialed number. After the query is launched, the destination number corresponding to the dialed number may be ascertained and returned to switch 128, assuming there is an appropriate entry in NCP 132. This destination number is then used to route the call through the other elements of network 100 to the appropriate destination, such as destination station 114.
It should be noted that the signaling path between the switches 128 and 130 and the NCP 132, denoted by signaling network 138, is distinct from the actual communication path between any of the originating stations 102 and 104 and any of the destination stations 114 and 116. That is, the query from the switch 128 to the NCP 132 employs out-of-band signaling to provide intelligent call services such as 800, 900 and ISDN services. In contrast, in-band signaling is carried along the same communication path as the data. For example, in a conventional telephone call, in-band signaling may be accomplished by touch tone dialing, in which numbers are pressed on the telephone keypad to transmit signals.